Models of prebiological phosphorylation

The hypothesis that contemporary metabolic pathways evolved from analogous chemical reaction sequences on the primitive Earth leads to a reexamination of models of prebiological phosphorylation. Present-day phosphate uptake by algae and bacteria seems to involve two transport systems: (a) An active transport process occurring at low external phosphate concentrations (as in unpollusive) process at higher phosphate concentrations (>10^?6 M) (as in the interstitial water of reducing sediments). Laboratory model experiments are described for the reaction of reducing sugars with orthophosphate in the presence of cyanogen, producing glycosyl phosphates. These reactions proceed with appreciable yields only at high phosphate concentrations (>10^?3 M), and may thus possibly serve as simulations of prebiological phosphorylation with diffusive transport, as it may have occurred in the interstitial water of reducing sediments.